Research at the Sevilleta LTER site in central New Mexico is concentrated on studies in desert grassland and shrubland communities, emphasizing biodiversity, species interactions and climate change. Aridland ecosystems are governed by key abiotic and biotic drivers, especially climate variability, fire, plant-microbe interactions, nutrient dynamics, and herbivory. On 4-5 August 2009 a lightening-caused wildfire burned approximately 3200 ha of native desert grassland, including several key long-term experiments that evaluate the potential impact of climate change on Chihuahuan Desert ecosystems. With this funding the investigators will monitor the interaction of microbial populations and desert grasses in their monsoon rainfall manipulation experiment to assess recovery rates of plant-microbial interactions. They will relocate a flux tower in unburned grassland and gather more detailed information on soil respiration and CO2 efflux in burned and unburned grasslands during post-fire succession, as well as in their nighttime warming and winter rainfall experiment. This will provide important information related to how desert ecosystems affect greenhouse gas emissions.
Broader impacts: Climate change is likely to alter the dynamics of ecosystems globally. This research will allow the investigators to assess system response to a type of natural disturbance, fire, that is likely to occur more often in the future. The research takes advantage of existing background and infrastructure to assess carbon loss and storage in a desert ecosystem. The project will support two undergraduate students from UNM, a minority serving institution, as well as provide a one-year research assistantship to a UNM graduate student. In addition, participants in this research include two faculty members at non-PhD granting institutions (Jose Herrera at Truman State University and Andrea Porras-Alfaro at Western Illinois University).
Project Summary. The Sevilleta LTER research in central New Mexico is concentrated on studies in desert grassland and shrubland communities, and piñon-juniper and riparian woodlands emphasizing transitions in space and time. Each landscape component is governed by key abiotic and biotic drivers, especially climate variability, fire, plant-microbe interactions, nutrient dynamics, and herbivory. On 4-5 August 2009 a lightening-caused wildfire burned approximately 3200 ha of native desert grassland including several key long-term climate change experiments at the Sevilleta. We viewed this fire as an opportunity to better understand how key components of this desert ecosystem are reconstructed during post-fire succession. These components include (1) plant-microbial coupling, (2) carbon fluxes during postfire succession, and (3) consumer-production linkages. To do so, we monitored microbial population dynamics in our monsoon rainfall manipulation experiment and found that grass-microbe interactions recovered quickly following fire. We also found that root growth was unaffected by fire despite the fact that aboveground plant growth remains low 3 years following the fire. Our flux tower data show that the burned grassland is still carbon neutral – over the long term they are neither a sink nor a source of carbon to the atmosphere. Finally, found that grasshopper communities recovered slowly following fire and the abundances of many species were limited by poor seasonal rainfall, which delayed vegetation recovery after the fire. Intellectual Merit: Aridland ecosystems account for 30-40% terrestrial ecosystems and, disturbances such as fire are likely to increase in a warmer future. Together our studies showed how fire altered the abundances of plant and animal species, and net primary production. Recovery was slow because of below average rainfall. Broader impacts: Climate change is likely to alter the dynamics of ecosystems globally. This research will allow us to assess system response to a type of natural disturbance, fire, that is likely to occur more often in the future. This research took advantage of existing long-term data sets and experiments to assess how arid grasslands respond to wildfire.
